In a saucepan, over medium heat, stir together the white sugar, British ale and butter.

Bring to a boil, then let simmer for 10 minutes.

Lower heat and add in the pumpkin pie spice and the brown sugar.

Once the sugar is dissolved, stir in the thickened cream.

Let cool before pouring into a glass jar. (The mixture will be runny).

Screw on a top, place in the fridge and let cool.

Butterbeer sauce will last for 3 weeks in the fridge.